1. Technical Field
The present invention relates to a device for fiber excess length stable control in an optical cable loose tube.
2. Related Art
The excess length refers to a length difference between an optical cable loose tube and an optical fiber generated as the optical cable loose tube contracts during coating and cooling crystallization. The excess length is one of the problems to be solved during the production of optical fibers and optical cables, and it directly impacts the transmission quality of high-frequency signals in the optical fiber. In the conventional process, a loose tube after secondary optical-fiber coating is cooled in a water trough, and is directly pulled by a tractor to a spool (see FIG. 1). During the cooling of the loose tube, the friction between water and the loose tube material causes an internal stress and a molecule (retraction) tendency in the loose tube, which makes the optical fiber generate excessive length with respect to the loose tube, thus affecting the quality of optical fiber products.